21427037 has 2 divisors, whose sum is σ = 21427038. Its totient is φ = 21427036.

The previous prime is 21427013. The next prime is 21427039. The reversal of 21427037 is 73072412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21031396 + 395641 = 4586^2 + 629^2 .

It is a cyclic number.

It is not a de Polignac number, because 21427037 - 2⁶ = 21426973 is a prime.

Together with 21427039, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21426997 and 21427015.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21427039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10713518 + 10713519.

It is an arithmetic number, because the mean of its divisors is an integer number (10713519).

Almost surely, 2^21427037 is an apocalyptic number.

It is an amenable number.

21427037 is a deficient number, since it is larger than the sum of its proper divisors (1).

21427037 is an equidigital number, since it uses as much as digits as its factorization.

21427037 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2352, while the sum is 26.

The square root of 21427037 is about 4628.9347586675. The cubic root of 21427037 is about 277.7499822439.

Adding to 21427037 its reverse (73072412), we get a palindrome (94499449).

The spelling of 21427037 in words is "twenty-one million, four hundred twenty-seven thousand, thirty-seven".